Scanning antenna

Abstract

A scanned antenna ( 1000 ) is a scanned antenna including antenna elements (U) arranged together, the scanned antenna including: a TFT substrate ( 101 ) including a first dielectric substrate ( 1 ), TFTs, gate bus lines, source bus lines, and patch electrodes ( 15 ); a slot substrate ( 201 ) including a second dielectric substrate ( 51 ) a slot electrode ( 55 ); a liquid crystal layer (LC) provided between the TFT substrate and the slot substrate; and a reflective conductive plate ( 65 ). The slot electrode includes slots ( 57 ) arranged so as to correspond to the patch electrodes. As seen from the normal direction to the first dielectric substrate, a plurality of spacer structures ( 75 ) provided between the TFT substrate and the slot substrate are arranged so as not to overlap with first regions (Rp 1 ) and/or second regions (Rp 2 ), where the first regions are regions that are within a distance of 0.3 mm from edges of the slots and the second regions are regions that are within a distance of 0.3 mm from edges of the patch electrodes.

The invention claimed is: 
     
       1. A scanned antenna including a plurality of antenna elements arranged together, the scanned antenna comprising:
 a TFT substrate including a first dielectric substrate, a plurality of TFTs supported on the first dielectric substrate, a plurality of gate bus lines, a plurality of source bus lines, and a plurality of patch electrodes; 
 a slot substrate including a second dielectric substrate, and a slot electrode formed on a first primary surface of the second dielectric substrate; 
 a liquid crystal layer provided between the TFT substrate and the slot substrate; 
 a plurality of spacer structures including a plurality of first spacer structures defining a distance between the TFT substrate and the slot substrate; and 
 a reflective conductive plate arranged so as to oppose a second primary surface of the second dielectric substrate with a dielectric layer interposed therebetween, the second primary surface being on an opposite side from the first primary surface, wherein: 
 the slot electrode includes a plurality of slots arranged so as to correspond to the plurality of patch electrodes; and 
 as seen from a normal direction to the first dielectric substrate, the plurality of spacer structures do not overlap with first regions and/or second regions, where the first regions are regions that are within a distance of 0.3 mm from edges of the plurality of slots and the second regions are regions that are within a distance of 03 mm from edges of the plurality of patch electrodes. 
 
     
     
       2. The scanned antenna according to  claim 1 , wherein the plurality of first spacer structures include a first spacer structure that includes a portion of a first metal layer including the plurality of patch electrodes. 
     
     
       3. The scanned antenna according to  claim 1 , wherein the plurality of first spacer structures include a first spacer structure that includes a portion of a second metal layer including gate electrodes of the plurality of TFTs and the plurality of gate bus lines. 
     
     
       4. The scanned antenna according to  claim 1 , wherein the plurality of first spacer structures include a first spacer structure that includes a portion of a third metal layer including source electrodes of the plurality of TFTs and the plurality of source bus lines. 
     
     
       5. The scanned antenna according to  claim 1 , comprising:
 a transmitting/receiving region defined by the plurality of antenna elements and a non-transmitting/receiving region around the transmitting/receiving region, wherein: 
 the plurality of first spacer structures include a first spacer structure in the transmitting/receiving region and a first spacer structure in the non-transmitting/receiving region; and 
 an area ratio of the plurality of first spacer structures per unit area of the transmitting/receiving region, as seen from the normal direction to the first dielectric substrate, is 0.05% or more and 0.6% or less. 
 
     
     
       6. The scanned antenna according to  claim 5 , wherein an area ratio of the plurality of first spacer structures per unit area of the non-transmitting/receiving region, as seen from the normal direction to the first dielectric substrate, is 0.05% or more and 0.6% or less. 
     
     
       7. The scanned antenna according to  claim 1 , wherein the plurality of spacer structures further include a plurality of second spacer structures that are lower than the plurality of first spacer structures. 
     
     
       8. The scanned antenna according to  claim 7 , wherein the plurality of second spacer structures include a second spacer structure having a height that is smaller than a height of the plurality of first spacer structures by 0.2 μm or more and 0.5 μm or less. 
     
     
       9. The scanned antenna according to  claim 7 , comprising:
 a transmitting/receiving region defined by the plurality of antenna elements and a non-transmitting/receiving region around the transmitting/receiving region, wherein: 
 the plurality of first spacer structures include a first spacer structure in the transmitting/receiving region and a first spacer structure in the non-transmitting/receiving region; and 
 an area ratio of the plurality of first spacer structures per unit area of the transmitting/receiving region, as seen from the normal direction to the first dielectric substrate, is 0.05% or more and 0.5% or less. 
 
     
     
       10. The scanned antenna according to  claim 9 , wherein an area ratio of the plurality of first spacer structures per unit area of the non-transmitting/receiving region, as seen from the normal direction to the first dielectric substrate, is 0.05% or more and 0.5% or less. 
     
     
       11. The scanned antenna according to  claim 9 , wherein where an area ratio of the plurality of first spacer structures per unit area of the transmitting/receiving region, as seen from the normal direction to the first dielectric substrate, is 1, an area ratio of the plurality of second spacer structures per unit area of the transmitting/receiving region, as seen from the normal direction to the first dielectric substrate, is 1 or more and 10 or less. 
     
     
       12. The scanned antenna according to  claim 9 , wherein where an area ratio of the plurality of first spacer structures per unit area of the non-transmitting/receiving region, as seen from the normal direction to the first dielectric substrate, is 1, an area ratio of the plurality of second spacer structures per unit area of the non-transmitting/receiving region, as seen from the normal direction to the first dielectric substrate, is 1 or more and 10 or less. 
     
     
       13. A scanned antenna comprising:
 a plurality of antenna elements arranged together; 
 a TFT substrate including a first dielectric substrate, a plurality of TFTs supported on the first dielectric substrate, a plurality of gate bus lines, a plurality of source bus lines, and a plurality of patch electrodes; 
 a slot substrate including a second dielectric substrate, and a slot electrode defined on a first primary surface of the second dielectric substrate; 
 a liquid crystal layer provided between the TFT substrate and the slot substrate; 
 a plurality of spacer structures including a plurality of first spacer structures defining a distance between the TFT substrate and the slot substrate; and 
 a reflective conductive plate arranged so as to oppose a second primary surface of the second dielectric substrate with a dielectric layer interposed therebetween, the second primary surface being on an opposite side from the first primary surface, wherein: 
 the slot electrode includes a plurality of slots arranged so as to correspond to the plurality of patch electrodes; 
 each of the plurality of antenna elements is defined by one of the plurality of patch electrodes, a portion of the slot electrode including one of the plurality of slots, and a portion of the liquid crystal layer that is between the one of the plurality of patch electrodes and the portion of the slot electrode; 
 the slot substrate or the TFT substrate includes a plurality of photospacers; 
 the plurality of photospacers include a photospacer having a height of 2 μm or more and 5 μm or less in a normal direction to the first dielectric substrate; and 
 the plurality of first spacer structures include a spacer structure including any of the plurality of photospacers. 
 
     
     
       14. The scanned antenna according to  claim 13 , wherein the plurality of first spacer structures include a first spacer structure that includes a portion of a first metal layer including the plurality of patch electrodes. 
     
     
       15. The scanned antenna according to  claim 13 , wherein the plurality of first spacer structures include a first spacer structure that includes a portion of a second metal layer including gate electrodes of the plurality of TFTs and the plurality of gate bus lines. 
     
     
       16. The scanned antenna according to  claim 13 , wherein the plurality of first spacer structures include a first spacer structure that includes a portion of a third metal layer including source electrodes of the plurality of TFTs and the plurality of source bus lines. 
     
     
       17. The scanned antenna according to  claim 13 , further comprising:
 a transmitting/receiving region defined by the plurality of antenna elements and a non-transmitting/receiving region around the transmitting/receiving region, wherein: 
 the plurality of first spacer structures include a first spacer structure in the transmitting/receiving region and a first spacer structure in the non-transmitting/receiving region; and 
 an area ratio of the plurality of first spacer structures per unit area of the transmitting/receiving region, as seen from a normal direction to the first dielectric substrate, is 0.05% or more and 0.6% or less. 
 
     
     
       18. The scanned antenna according to  claim 17 , wherein an area ratio of the plurality of first spacer structures per unit area of the non-transmitting/receiving region, as seen from the normal direction to the first dielectric substrate, is 0.05% or more and 0.6% or less. 
     
     
       19. The scanned antenna according to  claim 13 , wherein the plurality of spacer structures further include a plurality of second spacer structures that are lower than the plurality of first spacer structures. 
     
     
       20. The scanned antenna according to  claim 19 , wherein the plurality of second spacer structures include a second spacer structure having a height that is smaller than a height of the plurality of first spacer structures by 0.2 μm or more and 0.5 μm or less.